* CSI300 -0.9 pct; SSEC -1.1 pct; HSI -0.3 pct
* China's Big Four banks to report earnings this week
* Commodity sector sags on lower raw material prices
SHANGHAI, March 29 (Reuters) - China stocks sagged on Tuesday morning, as the momentum that pushed the market up more than 10 percent from February lows continues to wane with no stimulus in sight.
Trading volumes remain thin, suggesting that money is not flowing into equities, despite investors recently cutting their exposure to bonds, and also in the wake of real estate curbs in major cities such as Shanghai and Shenzhen.
The blue-chip CSI300 index fell 0.9 percent, to 3,141.76 points by the lunch break, while the Shanghai Composite Index lost 1.1 percent, to 2,924.10 points.
"Once bitten, twice shy. Investors burnt by last year's market crash are still too scared to enter the market, which is why we see a trading pattern of quick profit-taking," said Yang Hai, analyst at Kaiyuan Securities Co.
Selling intensified in late morning trading, as the start-up board ChiNext slid more than 2 percent.
The commodities sector fell, led by steelmakers, as a drop in Shanghai steel prices fuelled losses in other raw materials such as iron ore.
Banking stocks were soft, as China's Big Four state-run banks this week are set to report annual earnings growth that likely flat-lined, as a surge in soured loans continued unabated while economic expansion weakened.
Hong Kong stocks also weakened after the market resumed trading following the long Easter weekend.
The Hang Seng index dropped 0.3 percent, while the Hong Kong China Enterprises Index lost 0.4 percent.
On the corporate front, shares of Chinese beer giant Tsingtao Brewery Co Ltd fell 2.4 percent in Shanghai and nearly 3 percent in Hong Kong, after posting a drop in 2015 profits.
Shares of BYD Co Ltd were flat in Shenzhen and up 3.5 percent in Hong Kong, outperforming the market.
The Chinese automaker backed by Warren Buffett's Berkshire Hathaway Inc said its 2015 net profit rose more than six times over the previous year to a six-year high as green-energy car demand surged.
Reporting by Samuel Shen and Pete Sweeney; Editing by Jacqueline Wong